Tissu Humain et Types de Tissus

Introduction

• Human tissue is a complex combination of cells and extracellular matrix
• It forms various organs and body structures
• Four basic types exist: epithelial, connective, muscle, and nervous
• Each type has unique functions and structures

Epithelial Tissue

• Covers body surfaces, lines body cavities, forms glands
• Tightly packed cells with minimal extracellular matrix
• Functions: protection, secretion, absorption, excretion, filtration, diffusion
• Types: squamous, cuboidal, columnar
• Specialized structures: cilia, microvilli, tight junctions, desmosomes
• Location examples: skin, lining of the digestive tract, lungs, kidneys

Connective Tissue

• Supports, connects, and separates different tissues and organs
• More extracellular matrix than epithelial tissue
• Highly variable in composition and function
• Types:
  • Loose connective tissue: supports organs, fills spaces between tissues
  • Dense connective tissue: tendons, ligaments, strong support
  • Cartilage: firm, flexible support in joints, ears, nose
  • Bone: rigid support and protection, mineralized matrix
  • Blood: transports substances throughout the body
• Components: cells, fibers (collagen, elastic, reticular), ground substance

Muscle Tissue

• Specialized for contraction and movement
• Types:
  • Skeletal muscle: voluntary movements, striated appearance
  • Smooth muscle: involuntary movements, walls of internal organs (e.g., intestines, blood vessels)
  • Cardiac muscle: involuntary contractions, heart
• Structure and properties of muscle cells vary between types

Nervous Tissue

• Specialized for communication and control
• Composed of neurons and neuroglia (supporting cells)
• Neurons transmit signals throughout the body
• Neuroglia support and protect neurons
• Essential for: sensation, thought, movement, maintaining homeostasis
• Structure: cell body (soma), dendrites, axon
• Function: transmitting nerve impulses